Pendulum drift indicator



Au 7, 1951 E. e. PEEBLES 2,563,359

7 PENDULUM DRIFT INDICATOR Filed March 12, 1946 s Sheets-Sheet 1 V W/J/KMMQ 0 I (3. 52 INVENTOR.

BY W rro/zwsy.

Aug. 7, 1951 E. G. PEEBLES PENDULUM DRIFT INDICATOR 3 Sheets-Sheet 2 Filed March 12, 1946 E W t g M [p v A &

Patented Aug. 7, 1951 UNITED PATENT OFFICE vlassasss 'irnnnunnlu Dmrmumonron liEdgari Pe'ehles; Los Angeles, Calif. Appliauonmarchiz, 194Qseria1NG5a727 8"Claims. (Cl.33-*-205. 5)

My invention relates generally-to-"inclinomieters, and -more particularly -to "such idevices which are .known in the, art as driftrecorders andlare used to measure'the deviation from vertical of a well or 'hole'dr'illed' in the earth tda relatively great depth.

In the drilling of wells, itisxquite-important,

because of the property interest involved, to

know where thelower end of the well is. located. While angular or whipstock ,rdrillingimay oc- .casiona1ly be done; it isgenerallyfdesirable that the lower end of the wellbe asgnearly vertically aligned with the upperrendas possible; an'd to secure this result, it is desirable that the .welI'be substantially vertical for its entire length.

Should the bit or other drilling-tool,"which? is used in formingthe well, start to wander 'or deviate from the vertical, an'expe'rience'd operator may control-hisequipment sothatjthefdfill is returned to vertical. ."This ma befdonegrealdily if. the .deviation is. detected within afeWifeet :of the time that it starts; but-if'the angularpa'th has been followed for'several hundredfeet; it is veryudiflicult to: return "the -wel1-'toits; original alignment. Forthis reason, it is 'very 'desirable that the inclination-orthe deviation of'thewell from vertical be checked at'frequent intervals; and it is thereforeimportantthat a';metho'd:.of

checking be' provided which may be easily performed and consume a minimum oftime.

Furthermore, "since the :equipment "which is .used in" the: drilling' of -we'1lsireceives ,very'rough "treatment" and is subjected to severe ;mechanical shock, it is'necessary-toihave equipment which is ruggedly constructed;while still being sensitive enough .to provide ;accurate records. In additionybecause of thejroughftreatment'to which it is subjected, 'it' is advisable"to" have 'a self-checking means which 'willlindicate 'anyfdefeet or maladjustment of the instrument "so "that incorrect records may :be 7 immediately 'de showing the inclination of the wells at a gglven point, these previous instruments ,haye usually consisted of two separate recording devices which are operated simultaneously to provide two records which. should be lthesame, and fwhich, ,if

different, indicate defective 'equipmentforjimproper operation.

'It' has alsolbeen necessaryhinmany oft-these previous instruments to remove, the entireidrlll l5 'drill string from 'the'welli 12 string or mechanism suspending and rotating the drill in "orderi'to make the desired record; and where the well is several thousand feet deep, this has been such-a laboriousiandtime "consum- 5 in operation that-records were made: much; less frequently than they should befin ;order-':to' provide; the desired control *of the :well.

'It is therefore, thez majorobject of *mvinvention" to provide adrift recording apparatus whicli 10 may :easily; be operated-to provide any deslre d number of recor'dations 'for; a given" location ,of the instrument, so that; the accuracy' ofr'the; in- ;strument is constantly checked, and-which may be "used without the necessity of :rernoving ithe It is another objectof my invention to provide a drift recorder of simple and rugged construction, yet possessing sufficient accuracy to indicate very minor deviations of theweIl fr mthe-true .vertical. tilt is a further object, of my invention-toproyide such adevice wherein the making of the'record 7 may be controlled from the up er. endcofth'e; well 7 afterithe' instrument :has been" lowered into :it, the time and number of recordationswhich are made being under the control of'itheoperator at all-times. I jIt iS jStill "another object of-iny invention ;to provide such a device' which may i'be usediwlth If r s h vin anr em i ntlg xt r j'di sions,the same instrument b'eing adaptable for use with drills of all sizes byinieans ofiadapters which maybe. attached to thej-instrume'nt or Vsubs: which; are" assembled in the drill string when thejdr'ill is; attached thereto.

Another 'object of my invention isjto; provide a device which-willfurnishaj-record which instant y indicate zwh h e d i operatin prope ly, Whe h r t th embe and s b ct 1 to misa i me t o e i ha becom irty so that the "bearing surfaces noflonger f unction properly. 1

, These and other QbJ'ects of amy invention will beco e appa e t f om th Lfollqw n j de c ipt o Qof; a cpreferre'd and modified formnthereo fgand from ,thejdrawings, illustrating" those f forfrns, j in which:

F?ig. ,1 i is acrosspsectional view of jthef lower lend. or aldrill 'string with my improyed' rec ding 0 i ei oca e j her inq ndshq nii l evatio F g.2. is, a crosssectionalvi'ew of .lrnylprefcli ifld form; Ofidrift, recordin device taken, atZ-lflin .i li andfsh ins theJrel c v positi o th -Y .riO1 S :parts as eyta nea jwlulethe eevp asjcbeing raised orjlowered within-thelwell; H

Fig. 3 is a cross sectional view similar to Fig. 2, but showing the parts in their recording position when the device is at the bottom of the well;

Fig. 4 is a cross sectional view taken at 4--4 in Fig. 3, and showing the various parts at the head of the device in somewhat greater detail;

Fig. 5 is a plan view of the record element on which the inclination of the well is recorded;

Fig. 6 is a cross sectional view, somewhat similar to Fig. 2, of a modified form of my device as it appears as the instrument is being lowered into the well; and

Fig. 7 is a view similar to Fig. 6 of my modified form with the parts as they appear when the instrument is in the process of making a record.

Referring now to the drawings, and particularly to Fig. 1, thereof, the numeral indicates the lower section of a tool joint, such as is used for joining sections of drill pipe together. A drill collar H is threadedly connected to the tool joint I0, and a bit (not shown) is connected to the lower end of the drill collar in the usual manner. Between the drill collar l l and the tool joint I0, I have indicated an adapter or sub I2 whose function is to extend coaxially with the hole being drilled, and to center the drift recording apparatus [3 with respect to the hole and hold it aligned therewith. If the internal diameter of the drill collar II is oi the proper size, and

if the smaller internal diameter of the tool joint ID is of the correct dimensions, the adapter l2 will not be needed; but in order to permit the recording apparatus I3 to be used Where the drill collar II and the tool joint In have relatively large internal diameters, I make the recording apparatus relatively small and use an appropriate size adapter.

As shown in Fig. 2, the drift recording apparatus I3 comprises an outer housing [4, preferably cylindrical in shape, provided with outward extending radial flanges at its upper end. The lower ends of the flanges l5 are formed at an angle so that they will center the outer housing l4 when they bear against and are supported by a member having a circular opening, such as the adapter [2. The upper surface of the adapter l2, against which the lower edges of the flanges l5 bear, is preferably shaped at a corresponding angle so that the maximum support is provided for the upper end of the housing l4, and the latter is firmly held.

Rigidly attached to the lower end of the housing M, as by a threaded joint I6, is a spear [1, preferably formed of pipe or other convenient material, and provided with a guide head or point i8 which is removably attached to the spear I! so that heads ofvarious sizes may be readily interchanged. The guide head I8 is preferably formed of a plurality of flanges, somewhat similar to the flanges l5, connected together to form a generally conical member; and if the drift recorder is to be operated as indicated in Fig. 1, the maximum diameter of the conical portion is such as to permit the point to slide freely within the adapter [2, while permitting substantially The upper end of the cylinder is provided with a cap 22 to which a ring 23 is swivelly attached, and the ring may be supported by a wire line 28, used to lower and raise the recording apparatus in the well. When the recording device is supported by the wire line, the various portions of the device are in the position shown in Fig. 2. A boss 24 is formed on the upper end of the cylinder 20; and when the device is supported by the outer housing [4, the boss bears against the upper end of the housing, and the various members are in the position shown in Fig. 3.

The actual recording of the drift or deviation of the well from vertical is performed by a pendulum 25 which is pivotally mounted for rotation about two mutually perpendicular horizontal axes, and which has an upwardly projecting extension 26 provided with a point 21 on its upper end. The pendulum 25 may be of any suitable type, of which many are known in the art, but I have found that a non-magnetic pendulum, comprising a weight 30 connected by a rod 3| to a supporting member 32 which is also connected to the extension 26, forms a very suitable pendulum. The supporting member 32 may have a transverse opening 33 therein through which a cross member 34 may extend, the latter being provided with an upwardly projecting point 35 adapted to fit into a recess in the supporting member, so that the latter is free to turn about perpendicular horizontal axes, the cross member 34 preventing rotation about a vertical axis. The weight 30 is thus pendantly supported by the projection 35, and when properly adjusted, the extension 26 is thereby maintained in a vertical position.

To make a record of the inclination of the cylinder l5 with respect to the pendulum 25, the point 21 is pressed against a disk 36, made of Celluloid or other suitable material, and the disk is thereby punctured or indented. Such disks are known in the art, and are generally inscribed with a series of concentric circles 31, corresponding to degrees of angular variation. The disk 36 is preferably mounted so that it is spherically concave downwardly, thereby insuring that the point 21 will be perpendicular to it at all times.

,The disk is preferably held to a backing plate 40 by means of a threaded ring 4|, having an internal flange or shoulder 42, which bears against the disk. The backing plate 40 is carried by a stem 43 which is slidably mounted in a plug 44 threadedly connected in the upper end of cylinder 20. A spring 45 is placed around the stem 43 between the backing plate 40 and the plug 44 so that the disk 36 is yieldably held. The stem 43 is held within the cap 44 by a nut 46 and washer 41 at the upper end of the stem; and a spring 48, for a purpose hereinafter described, extends between the washer 4'! and the cap 44 to oppose the urging of the spring 45. The backing plate 43 is thus capable of vertical movement in either direction, but will tend to return to a normal position determined by the springs 45 and 48.

To move the point 21 toward and away from the disk 36, the cross member 34 is connected, in a manner now to be described, to the outer housing l4 so that movement of the latter with respect to the cylinder 20 is transmitted to the pendulum 25. As shown in Figs. 2 and 3, this connection includes a cross pin 50 which extends across the spear I! at a point below the lowermost position of the end of cylinder 20. A spring 5|, designed to operate in both compression and ten- Qsion, is attached to the 'crosspin 50 and extends upwardly theref rom to a connecting rod 52. A partltion closes the lower end ofcylinder' 20, fand a packing'154 permits the connecting rod-52 to move through the vpartition while preventing the passage of fluid. 'The'upper end of connecting rod 52 is connected to a hollowpistonf55' mounted within 1 the cylinder 20 and provided withpiston rings 56 which maybe of cork; metal, or other suitable material. The lower end "oi the piston 55 is closed, and the connectingrod 5 2 "is preferably threadedly connected to the closure. The upper end of the piston is open," and thej'crossfbar 34 is mounted thereon to'j extend across the piston. j Thependulum 25 thus'has'its lower; half surrounded by the piston 55while the j ei'gtension ZG being' above the cross "member, is

'notfenclosed bythe piston. 7 H V v t 'I'he pendulum 25 is damped by completely filling the cylinder 20 with oil so that when the cap 44 is installed in the up'per'end of the cylinder,

no air remains in the latter to cause foaming of the oil. The oil, in "addition to damping" the pendulum 25 so that it comes to rest relatively quickly, also has the effect of retarding the movement of the piston" 55 so that 'if the outerhous- 'ing i4 issuddenly movedupwardlywith respect fto' the cylinder 20, the movement of the piston 55, will be less rapid and there will be less posslbility of hitting the point 27 against the disk 35 with'sufiicient force to bend the extension" 26,

or otherwise damage the pendulum. While the action of the piston rings 56 is to tend to" seal the space between the piston 55 and the wallsof the cylinder 20, a certain amount of'oil will flow past the piston and permit the latter to move upwardly. The action of the piston 55' within the cylinder 20 is thus similar to the well known dashpot; andfas a result, the previously mentioned retarding action of the oil is provided.

This retarding action, it is to be understood, permits the point 2'lto be moved against the disk 35 with a firm, constant motion, while preventing any impact'which would tend to damage the instrument. In addition, the relatively slow upward movement of the piston 55 permits the pendulum 25 'to come to rest before contact is made between the point 21 and the disk'tfi. The spring 5| also prevents excessive pressurefrom "being exerted by the point 27, since the-spring the connecting link between the'p'iston and the spear ll and greater movement of the spear l! with respectto the cylinder 26 merely results in compression of the spring, and amn spoiiaing slight increase in pressure of the point 21 against the disk 35, instead Ofper'mitting the"entire weight of the cylinder 20 with itsassociated members to be supported by the point.

A In the" drilling of wells, it'is customarfto force a so-called mud to circulate through the well, carrying the chips of rock and other debris with it out of the well so that the bit may always bear against and touch the earth,'rather than the pieces of rock which have already been cut. The depth of many present day 'wells'is rneasure d'in thousands of feet; and as a consequence, the hydrostatic pressure of the mud at :the bottom of the well is many thousand pounds. The exterior of the cylinder 26 is subjected to this high pressure, and if no provision were made for changing the pressure on the inside of the cylinder, the latter pressure would tend to rer'n'ain at substantially atmospheric pressure. Under .6 able that if the normal separation between them wer smallfthe point '21 -'wou1d be forcedagainst the disc-"-35 and mark --the l-atter. -Thisuncontrolled niovementwould give a false indication 5 of' the inclination "of the-well, and -Would-pret the-apparatus from operating normally" and p'roperly wlien the adapter; -I lie reached.

T0 b'vercoine this difilculty, I have developed inear-assure" equalizer shown'inFig; 4, and includii'igfihe "stem"-43 whic'hcarries the" backing p te-*40;""and the spring-d8; Since-thering 23*ls ween-1y i'otatably mounted in the" cap 'ZZ, there (1 any ample opportunity for the inud to enter the can -22 and equalizethe pressure between the in'slde a'i idtheoutside' of the-cap. The pressure "n' the slde 'of the cap acts u'pon' the st'm 43, umg to roree it, 1 against the urgingof i ens lfl-f into tha'interiorof thecylinden Any 5 e inent of the'stem '43 into the interior ofthe cy inder will tend to increase the "pressure herein, and-since oil is essentially a non-cemressiblefiuidjonly a verysmallm'ovement of the "'st'ern' is necessai'y. When the instrument is'rai'Sed to the tep of'the 'well; the *pressureurging the ste'm' '43 inwardly is -decreased,- and consequently 'the spring as and the increased pressure within thecylinder fli urge thestem outwardly to "euuaiiz the pressure. Since the stem- 43 is not -'-siibjeetd"=to the rough treatm'ent th'at manyof th remaining-parts ofthe instrur'nent are, and since iti'rnoiles a relativelyshort distancefit is 156'ssib'le to p'rovi'de'a verygoodsealfbetween the stein' and the cap 44 so that mud will not "enter --the"cS'Iinder-'2D.

Operation of preferred ,form

When, in the drilling of a'welL-the inclination thereof-is tobedetermined, the instrument I3 is lowered into the well by meansof the wire line 28. The actual drilling operations are halted While the-measurements and records'are being made; but it is not necessaryto remove the drill or drill string from the hole in order to use my instrument. The instrument l3is lowered until the spear l'l enters the adapter 12, and the flanges l5 bear against and are centered by the collar at the upper end of the adapter. The lower end of the spear l'l is centered bythe flanges forming the point I8, and the lower end entire instrument and adapter are coaxial with the drill'collar II, which in turn is coaxial-with the lower end of the well. As the instrument l3 has been lowered, the pressure exerted upon it by the-mud used in the drilling operation has been steadily increasing, and as a result, the stem 43 hasbeen moved downwardly into the interior of the-cylinder '20 so that the pressure within -that cylinderhas been substantially-equal- -ized at all times with the pressure on the outside thereof. I The cylinder is connected by the cap 22 tethering 23, and consequently the weight -of the-cylinder and the equipment directly con- -'--nected to it have been supported by 'the'ring 23. -Inaddition, the outer housing l4 and the spear lThave been in their lowermost positions; with Y respect to the cylinder 20 and the lower'end-of the outer housinghas'been resting upon the collar 2] so that the weight ofthe spear and-the 70""duter housing are carried by the cylinder.

I As the instrument 13 reaches the lower end of th'well, the flanges l 5 fit within the collarof the adapter l2,"centering the instrument and supj 'porting the weightof 'theouter housing "I4 and 76""the "spear l1. Further 'aownwarwmovement '0f of the adapter is centered by'springs so that the was the wire line 28 permits the cylinder 20, under its own weight, to continue its downward movement until the boss 24 at the upper end of the cylinder has moved downwardly a sufficient distance to engage and be supported by the upper end of the outer housing [4. An additional amount of the wire line 28 will almost invariably be lowered into the well, and this will rest upon the upper end of the cylinder 20, tending to force it to its lower limit of travel. The piston 55 has heretofore been at the lower end of the cylinder, since the connecting rod 52 and the spring have urged it in this direction by reason of the position of the pin 50 and the housing I4 with respect to the cylinder 20. However, when the cylinder is moved downwardly with respect to the outer housing I4, so that the latter supports the weight of the cylinder, the lower end of the cylinder is moved closer to the pin 50, while the spring 5| and the connecting rod 52 tend to maintain the piston 55 in the same position with respect to the housing, 1. e., farther up in the cylinder. Because of the dashpot action of the piston 55, the latter is not stationary, but instead moves downwardly with the cylinder 20 and then slowly returns toward its original position as the oil from above the piston flows by the latter and between the piston rings 55 and the cylinder to a point beneath the piston. At the start of this upward movement, the piston 55 has been moved downwardly, while the pin 50 has remained stationary. The spring 5| is therefore compressed, and thus exerts a continuing upward force on the piston 55 while the latter moves and carries the point 21 into contact with the disk 36. As the connecting rod 52 moves into the cylinder 20, the increased volume thereof within the cylinder tends to increase the pressure on the oil within the latter; but the spring mounting of the back plate and the stem 43 permits these members to move so that the pressure within the cylinder remains substantially constant. Since the diameter of the stem 43 is considerably greater than the diameter of the piston rod 52, only a relatively short movement of the stem is necessary to balance a relatively long movement of the connecting rod.

After the wire line 28 has been lowered to the point where the entire weight of the instrument I3 is supported by the flanges l5, the line is allowed to remain slack until it is certain that the point 2! has marked the disk 35. At that time, the line may be raised a few feet so that the point I8 is above the adapter l2, whereupon the natural torsional forces in the line will rotate the instrument 13 as it hangs freely suspended in the well. If the instrument is again lowered so that the flanges Hi again support the entire instrument, the process of recording the position of the pointer 2'! will be repeated. The possibility that the instrument [3 will have the same rotational position with respect to the adapter [2 is extremely remote, and if the instrument is in proper working order, the second mark in the disk 36. should be the same radial distance from the center of the disk as the first mark but angularly displaced from it. A check on the accuracy of the instrument is thus readily available, and by making a series of marks, a multiple check is provided, which, in the case of a malfunctioning of the instrument, will indicate the cause of the malfunction. When the desired number of recordings have been made, the instrument is removed from the well by the wire line 28, and when it is once again on the surface, the cap 22 and the plug 44 are removed, and the disk 36 is removed from the backing plate 40. The position of the marks with respect to one of the concentric circles 31 provides a record of the inclination of the well; and if any corrective action is indicated, it may be taken at this time. Since it is unnecessary to remove the entire drill string and drill from the well in order to make this record, the drilling crew can more easily be induced to make records frequently and thus correct any deviations before the well has been drilled so far at this angle as to make such correction impossible. Since the records are in the convenient form of small disks, they may be readily marked for identification and then filed for future reference.

It will sometimes happen that the internal diameter of the tool joint [0 and the drill collar H are of such size and so related that it is undesirable or unnecessary to make use of the adapter 12. Under these circumstances, it is often desirable to have the flanges iii of such a size that they will center the upper end of the instrument [3 with respect to the drill collar and tool joint, and to form the flanges of the point [8 so that the lower end of the spear is similarly centered. If the flanges i5 and i8 are thus of the same overall size, it will be seen that there will be no shoulder or other restriction for the flanges l5 to rest upon. This will be apparent from the fact that any shoulder which would support the flanges l5 would also support the tip I8. The flanges IE will thus be devoid of any longitudinal support, though they will receive lateral support from the walls of the tool joint or of the drill collar; and the point l8 will thus travel downwardly until it is stopped by some constriction which will support it. The operation of the instrument i3, however, will be the same in both instances, since the spear I7 is firmly connected to the outer housing M at the joint i6; and any movement or lack of movement of one of these members is transmitted to the other so that the cylinder 28 operates in its normal fashion.

Construction of modified form In Figs. 6 and 7 I have shown a modified form of construction wherein the making of the record is secured by the moving of a lever, rather than by the movement of a piston. The method of operating this form of instrument is substantially identical with the method of operating my preferred form, but the internal operation of the instrument itself is different. As seen in the drawings, the numeral 69 indicates a head having a shape somewhat similar to the flanges l5 and serving the same purpose, i. e., the centering of the instrument with respect to the well, and the supporting of the instrument. The head 60 is provided with a central annular recess at its lower portion, and a ring 6! is threadedly mounted in the recess, but does not extend the full depth thereof, so that a central annular cavity 62 is provided in the head. An outer housing 63, somewhat similar to the outer housing [4 of my preferred form and likewise cylindrical in shape, is threadedly attached to the ring 6| to extend downwardly and carry a spear 64 having a point 65 at its lower end. The spear 64 and point 65 may be similar to the spear ll and point H! of my preferred form, and they serve the same purpose and operate in the same manner.

Within the housing 63 is a cylinder 55, similar to the cylinder 28 and closed at its lower end by a plug 61 having therein a pressure equalizer of the type used in my preferred form, or, alternatively, a flexible diaphragm 88 for the same purpose. The upper end of the cylinder 66 is closed by a cap member l6, having a partition 1! therein immediately above the upper end of the cylinder; and an orifice 16 provides a restricted pas sageway through the partition. The cap member H! is hollow above the partition H so that it is generally cup-shaped with flanges extending below the partition which are threadedly joined to the cylinder 66. A plug 12 is threaded into the upper end of the cap member 16 to form a chamber 19, and a hoisting ring I similar to the ring 23 of my preferred form, is mounted on the plug.

A pendulum 14, similar in all respects to the pendulum 26 of my preferred form, is mounted within the cylinder 66 by means of a cross member 15, similar to the cross member 34, and rigidly attached to the cylinder; and an upwardly extending projection 16 carries a point Tl on its upper end in a manner sinllar to that previously described. Immediately above the point 11 is a disk 36 held to a backing plate 86 by a threaded ring 8|. A stem 82, similar to stem 63, supports the backing plate 86 and extends through the partition ll and into the chamber 19. The upper end of the stem 62 is provided with a flange 83, and a compression spring 84 surrounds the stem and extends between the flange and the partition H, urging the stem 82 and the backing plate 86 upwardly so that the latter bears against the partition.

When the backing plate 66 is in its uppermost position, bearing against the partition I l the disk 86 is above the point H and the latter is free to move with respect to the cylinder 66 and thereby indicate the true vertical at all times. To bring the disk 36 and the point 11 together so that a record may be made, I use the lever system indicated. This lever system includes a lever 65 which is pivotally mounted in the wall of the cap member by the bearing 69, and has one arm extending through the wall to fit within the annular space 62 between the head 66 and the ring 6|. This outer arm is provided with a spherical end portion 86 so that as the lever 65 is rotated, the center of the sphere does not change its position with respect to the head 66. A seal 81, of any suitable type, is provided in the wall of the cap member 10 so that mud will not be forced into the chamber 19, and fluid will not escape therefrom. The inner end of the lever 86 is provided with a spherical end 88, similar to the spherical end 86, which bears against the flange 83 so that downward movement of the sphere 68 will be transmitted to the stem 82 and force the backing plate 86 down. The cylinder 66 and the chamber 19 are both completely filled with oil, and any downward movement of the stem 82 will'cause oil to fiow from the cylinder into the chamber. The rate of flow may be controlled by the size of the orifice I8, and the motion of the stem is thus retarded by a dashpot action similar to that of the piston 55 of my preferred form.

To cause the movement of the lever 86, the cylinder 66 and the cap member 16 are moved downwardly with respect to the head 66,thereby moving the bearing 89 of the lever in the wall of the cap member downwardly while the outer spherical end 86 remains stationary. The lever 85 amplifies this movement so that the inner spherical end 88 moves downwardly with respect to the cap member 1a, urging the stem 82 downwardly so that oil is forced from cylinder 66 into the chamber 19 at a relatively slow rate, determined by the orifice 18, and the disk 36 is moved against the point 1'! to make a record of the position of the latter, as described in my preferred form. The position of the various members at the time of recordation is shown in Fig. 7.

Movement of the cylinder 66 with respect to the head 66 is accomplished in a manner similar to that described in connection with the move ment of the cylinder 26 with respect to the outer housing M of my preferred form. In my modified form, the head 66 is provided with an inwardly extending flange 9| which is adapted to bear against the upper end of the cap member 10, and which supports the head, the outer housing 63, the spear 64, and all associated equipment when the entire instrument is supportedby the rin 13. Under these conditions, the cylinder 66 is in its uppermost position with respect to the head 66 and the outer housing 63, and the parts are in the position shown in Fig. 6.

When the instrument has been lowered into a well until some restriction bears against the head 66 or-the point 65 and thus supports the entire weight of the instrument, the cylinder 66 moves downwardly with respect to the outer housing 63 until the plug 61 in the lower end of the cylinder bears against an inwardly extending flange or ring 92 welded or otherwise firmly attached to the outer housing. The ring 92 thus supports the entire weight of the cylinder 66 and all the members attached to it; and by properly-locating the ring", the movement of the stem 82 will be just sufficient to cause the point 1! to puncture the disk 36 without placing a load on the extension 16 suff cient to damage the pendulum 14, its support 15,

F or the extension itself. This position is shown in Fig. 7.

Operation of modified form To use my modified form of drift recording apparatus to determine the inclination of a Well, an adapter l2 may be inserted between the drill collar H and the lower section I0 of the tool joint, or, if the internal dimensions of the tool joint and the drill collar are such as to make this practical, the adapter may be omitted, as described in connection with my preferred form. To make a record of the inclination of the well at its lower end, the modified form of recording apparatus is lowered into the well by means of a wire line attached to the ring 13, the instrument being lowered until the head 60 is supported by the upper end of the adapter l2, or until the point 65 is held by some constriction. Prior to the time when the head 60 or the point 65 is heldby the constriction in the well, the entire weight of the instrument is supported by the ring 13 and the various portions of the device are in the position shown in Fig. 6. There it will be seen that the upper end of the cap member 1|] bears against the inwardly extending flange 9| of the head 66 and thus supports the weight of the head, the outer housing 63, and the point 65. The cylinder 66 is in its uppermost position with respect to the head 60, and the lever 85 is in its upper position, permitting the stem 82 and the backing plate 86 to remain in their upper limiting positions. The pendulum 14 is supported by the cross member 15 so that the former is free to move and to maintain a vertical position at all times while oil inside the cylinder 66 surrounds the pendulum to damp any oscillation of the latter, and the extension 16 thus quickly comes to rest in a vertical position. The disk 36 is above the point l1 and spaced therefrom so that the disk provides no frictional restraint for the pendulum as the instrument is being lowered into the well.

When the recording device reaches the bottom of the well, the movement of the head 60 and the spear 65 is stopped by the restriction previously mentioned, and continued lowering of the wire line will permit the cylinder 66 to move downwardly by its own weight until stopped by the ring 92. The cylinder 66 has thus been moved downwardly with respect to the head 60; and when the cylinder has reached its lowermost position, the various elements are in the position shown in Fig. 7. In reaching this position, the movement of the cylinder 66 has carried the bearing 89 of the lever 85 downwardly, while the outer spherical end 86 has remained at the same height, thereby forcing the inner spherical end 88 downwardly with respect to the bearing, and urging the stem 82 and the flange 83 downwardly. This downward movement of the stem 82 is yieldably'opposed by the spring 84; and the restricted flow of oil through orifice 18 further retards the speed of movement of the stem. As stem 82 has moved downwardly, the backing plate 80 and the disk 36' have been moved toward the point 11 until the latter has engaged and punctured the disk 36. By puncturing the disk 38 as mentioned, a permanent record is made of the inclination of the well at the point where the instrument is located. A second record may be made by raising the entire instrument a short distance by thewire line, and then again lowering it, as with my preferred form. The natural torsional instability of the wire line will rotate the instrument in a plane perpendicular to its axis, and it is almost certain that the instrument will have been turned with respect to the restriction, and the well, when the second record is made. By making two or more records of the inclination at a given point in the well, a double or multiple check is provided on the accuracy of the instrument, and any inaccuracy or malfunction may be immediately detected and corrected. In this way, accurate records may be kept of the inclination of the well throughout its entire length, and there will be little reason to disregard any record which shows a deviation by assuming it was caused by a defective instrument. It will be seen that in both the preferred and modified forms of my drift recording apparatus, I

I have provided a device which may be operated to provide a check on its own accuracy, and which does not have any timing device or mechanisms which will make a record of the inclination of the device at a predetermined time after,

it is lowered into the well, regardless of its position along the length of the well. Instead, the device is operated at a predetermined point in the well where a restriction is placed, and the record is made at this point regardless of the length of time it has taken to lower the instrument to this position.

While I have shown and described a preferred and modified form of my invention, I do not wish to be limited to the particular form or arrangement of parts herein described and shown, except as covered by the following claims.

I claim:

1. A drift recording apparatus for measuring the inclination of a member with which it is aligned and including: a housing; a container within said housing and movable with respect thereto; a first means cooperating with said housing and said container whereby the latter may support said housing when in a first position; a second means cooperating with said housing and said container whereby the latter may be supported by said housing when in a second position; pendulous means within said container having a recording element attached thereto; a record blank Within said container normally spaced from said recording element; a pistonlike means within said container adapted to move said recording element and said record blank into and out of engagement; and means transmitting the movement of said container with respect to said housing, to said piston-like member and thereby move said recording element and said record blank together to record the inclination of said container when the latter is in said second position, and to separate said element and blank when said container is in its first position.

2. A drift recording apparatus for measuring the inclination of a member with which it is aligned and including: a housing; a container within said housing and movable with respect thereto; a first means cooperating with said housing and said container whereby the latter may support said housing when in a first position; a second means cooperating with said housing and said container whereby the latter may be supported by said housing when in a second position; pendulous means within said container having a recording element attached thereto; a. record blank within said container normally spaced from said recording element; a piston-like means within said container adapted to move said recording element and said record blank into and out of engagement; means retarding the movement of said piston-like member with respect to said container so that said recording element and said record blank are forced into engagement without impact; and means transmitting the movement of said container with respect to said housing, to said piston-like member and thereby moving said recording element and said record blank together to record the inclination of said container when the latter is in said second position, and to separate said element and blank when said container is in said first position.

3. A drift recording apparatus as described in claim 2 wherein said retarding means includes: a substantially non-compressible fluid surrounding said piston-like member; and a restriction limiting the flow of fluid from one end of said piston-like member to the other.

4. A drift recording apparatus adapted to be lowered into a hole to measure the inclination thereof and including: a tubular housing; a member attached to said housing adapted to align and support the latter at the lower end of said hole; a container within said housing axially movable with respect thereto; means cooperatively associated with said housing and said container whereby the latter supports said housing when said apparatus is being lowered into said hole, and said container may be axially lowered to a second position with respect to said housing when the latter is at the bottom of said hole, said housing then supporting and aligning said container; a first piston extending from the exterior to the interior of said housing, adapted to move inwardly as the exterior pressure on said container increases, and to move outwardly as said exterior pressure decreases, whereby the interior and exterior pressures on said container are maintained substantially equal; a record blank mounted within said container and moved geodetic 13 therewith; a pendulum withinsaid container; a, recording element attached to iSdidPGlldullillllfOr operation thereby; saidelementnormallybeing spaced fromsaid record-blank; a second 1 piston within saidconta-inerand movable withgrespect thereto; saidpistoncarrying saidpendulum and said recording element; a restricting, member adapted to -lirnitthe -flow-ofa substantially non,- compressible fiuidwithin said" container from one-end ofsaid second piston to the -other;.,where;-

by the movementorsaid second-piston within said container is retarded; a-connectingrod attached to said second piston-and extending through a Wall of said container; and a spring meanscon: necting said connecting rod to' said housing, whereby downward movementofsaid container with respect to saidhousingwillcause said record blanlnand said recordingv element to be urged togethenprovidinga rec-ordzof 'the inclination of said hole each time said container is lowered with respect to said housing, and said element and blank are urged apart when said container is raised with respect to said housing.

5. A drift recording apparatus adapted to be lowered into a hole to measure the inclination thereof and including: a tubular housing; a member attached to said housing adapted to align and support the latter at the lower end of said hole; a container Within said housing axially movable with respect thereto; means cooperatively associated with. said housing and said container whereby the latter supports said housing when said apparatus is being lowered into said hole, and said container may be axially lowered to a second position with respect to said housing when the latter is at the bottom of said hole, said housing then supporting and aligning said container; a flexible diaphragm mounted in a wall of said container and subjected to both the internal and external pressures acting on said container, said diaphragm moving inwardly as said external pressure increases, and outwardly as said external pressure decreases, whereby the internal and external pressures acting on said container are maintained substantially equal; a pendulum mounted within said container and moved therewith; a recording element attached to said pendulum for operation thereby; a record blank within said container and normally spaced from said recording element; a carrier for said record blank, movable with respect to said container; a restricting member adapted to limit the flow of a substantially non-compressible fluid within said container from one end of said carrier to the other, whereby the movement of said carrier is retarded; a lever pivotally attached to said container, extending through the wall thereof with one end engaged by said housing and the other end bearing against said record blank carrier; and spring means urging said carrier against said lever to hold said record blank out of contact with said recording element until said container is moved downwardly with respect to said housing, whereupon said lever forces said carrier downwardly, against the urging of said spring, and moves said record blank against said element, whereby a record of the inclination of said hole is made each time said container is lowered with respect to said housing, and said blank and said element are separated each time said container is raised.

6. A drift recording apparatus which includes: a housing having a chamber therein; supporting means at the upper end of said housing; a pistonislidable within-said-chambenmovable along; the.- longitudinal; axis oft said; housing, a, connectinggrodiattacheditor-saidpiston and extend-a ing through said; housing; forv movement with. respecttothe :latter; anoperatinamemben pro: jeeting; below said housing; and movable; with; respect thereto; resilient zmeansr connecting said operating membentosaid connecting r drwherer theret as. record: blank within said chamber normally spaced from said recording element; and means attached .tozsaidzpiston for moving said recording elementandsaid reoord.-, blank into and out of engagement to .thereloy record.

the inclination of said housing each time said operating member is moved toward said housing.

7. A drift recording apparatus which includes: a housing having a chamber therein; supporting means at the upper end of said housing from which the apparatus may be suspended; a piston within said chamber, slidable along the longitudinal axis of said housing; a connecting rod attached to said piston and extending through the lower wall of said chamber for movement with respect to the latter; an operating member extending below said housing and movable with respect thereto, said operating member assuming its most extended position when said apparatus is suspended from said supporting means, and assuming its most retracted position when the weight of said housing rests upon said operating member; spring means between said operating member and said connecting rod for transmitting the motion of said operating member to saidconnecting rod; a fluid within said chamber restraining the rate of motion of said piston, said piston thereby acting in the general manner of a dashpot plunger, and normally being in a first or lowermost position when said operating member is in the most extended position, and in a second or upper position when said operating member is in its most retracted position, said piston moving slowly between its first and second positions regardless of the rate of movement of said operating member; pendulous means within said chamber having a recording element attached thereto; a record blank receiving member within said chamber normally spaced from said recording element; and means attached to said piston for moving said recording element and said record blank receiving member relative to each other, said recording element making a record on a record blank held by said record blank receiving member to thereby record the inclination of said housing each time said piston is moved to said second position.

8. A drift recording apparatus which includes: a housing having a chamber therein; operating means projecting from said housing and movable along the longitudinal axis thereof; a piston within said chamber, slidable along the longitudinal axis of said housing; a fluid within said chamber; means restricting the flow of said fluid from one end of said piston to the other, whereby the rate of longitudinal movement of said piston is materially retarded; a connecting rod attached to said piston for movement there- 15 with; spring means coupling said operating member to said connecting rod to form a resilient connection therebetween whereby a rapid movement of said operating member with respect to said housing will not cause an equal and simultaneous movement at the same rate by said piston, but the movement of said operating member urges the corresponding movement of said piston; pendulous means within said chamber having a recording element attached thereto, said pendulous means connected to said piston for movement therewith; and a record blank receiving member within said chamber normally spaced from said recording element but positioned to have a record blank carried by it, engaged by said recording member to make a record thereon each time said piston is moved toward said record receiving member.

EDGAR G. PEEBLES.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number 16 UNITED STATES PATENTS Name Date Elliott Jan. 13, 1933 McLaughlin et a1. Apr. 11, 1933 Webster Apr. 25, 1933 Cavins Nov. 14, 1933 Welikonov Nov. 30, 1937 Strootman Mar. 1, 1938 Lottinger Nov. 15, 1938 Strength Apr. 16, 1940 Cooper et a1 Oct. 29, 1940 Passler Nov. 19, 1940 Opacensky Nov. 23, 1943 Beal Aug. 20, 1946 Schadel May 13, 1947 FOREIGN PATENTS Country Date Great Britain 1906 

